SOME NEW SOUTH AMERICAN BIRDS. 



By Harry C. Oberholser. 



Assixtdiil Omitlinloght, Depiirtiiu'iif of A</ririi/li(n\ 



Duriiip- the course of various recent systeniiitic researches in the 

 bird collection of the United States National ^Vluseum, the following- 

 South American species and subspecies, apparentl\^ new, were inci- 

 dentally brought to light. They for the most part belong to the 

 Tyrannid.'v and other mesorayodian families. In several instances the 

 specimens had been for a long time in the United States National 

 Museum collection, but either undetermined or misidentitied. 



For privileges of investigation and publication, as well as for many 

 accessory courtesies, the thanks of the author are due Mr. Ridgway, 

 the curator of the division. In three cases where material from other 

 museums forms the basis of description, indebtedness to the proper 

 source is acknowledged. 



Family FORMICARHD^E. 



THAMNOPHILUS TEPHROGASTER, new species. 



C/icirs. xp. — Similar to ThainnophHus caerulescens in form and gen- 

 eral color, but ditlers in having the abdomen and crissum pale slate 

 gray instead of white, the lower tail-coverts barred with blackish. 



Descri2^t!on.—Ty\)Q, adult male. No. 32846, U.S.N.M.; Bahia, 

 Brazil. Pileum, nape, and middle of back black, the latter with large 

 concealed spots of pure white; remainder of upper surface, the super- 

 ciliary stripe, sides of head and neck slate color, the lores and auric- 

 ulars mixed with blackish; tail black, broadl}^ tipped with white, and 

 with a bar, or lengthened spot, on the middle of the exterior web of 

 each of the outer rectrices; wings fuscous, the secondaries margined 

 externally with slate color, the primaries narrowly with white, the 

 superior wing-coverts all black with broad white tips; lower surface 

 slate gray, paler posteriorly, where obsoletely barred with grayish; 

 crissum light slate gray, barred rather indistinctly with slaty blackish; 

 lining of wing grayish white. Length of wing, 71 mm.; tail, 66 mm.; 

 exposed culmen, 13.5 mm.; tarsus, 23 mm.; middle toe, 11- mm. 



This new Thamnophihtx. has apparently hitherto been confounded 



Proceedings U. S. National Museum, Vol. XXV-No. 1276. 



59 



